This disclosure is directed to a system for initiating and ending formation fluid flow in a plurality of formations intercepted by a well borehole. Two or three examples of this type of well will suffice to describe and set the stage for the equipment of this disclosure. Consider as an example a cased well borehole which passes through three or four production zones. One mode of production is to case the well, form perforations into the separate multiple formations where production is obtained, and produce each zone into an isolated zone in the well borehole. That is, a packer is placed above and another placed below the zone so that zone production is isolated in the region of the particular zone. Production is removed from the zone by means of a production tubing string dedicated to that particular zone. This is somewhat complicated in that each zone has its own production tubing string and accordingly, the top zone is isolated by packers which must permit the production tubing strings of the lower zones to pass through; this requires a relatively complex completion procedure. If there are three production zones of interest, the packers for the top zone will connect with only one tubing string but the production tubing for the lower two formations will pass through, creating a relatively complex packer installation at the top zone. The bottom most zone of course remains relatively simple.
One choice that is not a choice at all is to permit all the zones to flow into a production tubing string without zone or formation isolation. This can be done provided a single production sand is isolated at different elevations in the well; however, it is generally undesirable to do this because there are differences in production rates from the zones. In part, this stems from the fact that the zones may have different pressures. Indeed, it is possible for one zone to produce because it has a high pressure drive into the cased well and yet another zone may steal production because it has a relatively low production rate into the well. In that instance, production from the high pressure formation may have sufficient pressure drive that the production fluid is driven from the high pressure formation into the well and out of the well because it flows into the formation which has a comparatively reduced pressure drive.
Another example of this problem derives from the water that is commingled in various production zones in an oil field. For instance, there may be a first sand which has high pressure with no water mixed with the oil. There may be a second formation where the oil is floating on top of produced water. The produced water can be fresh water or salt water. There may be other sands or formations where there are known water drives which provide produced water at various times in the produced formation fluids. It is usually undesirable to commingle water from the different formations. It is undesirable because the water in one formation may be fresh water and the water in another formation may be salt water. It is also undesirable because there may be sufficient differences in the water pressures that the high pressure formation will deliver water at such a volume and pressure that it forces into the low pressure formation. It is therefore generally undesirable that water as well as hydrocarbon or petroleum products be produced and commingled in a well borehole merely by directing perforations into a multitude of formations and delivering the formation fluid flow into a commingled zone in the cased well.
In testing for produced water purity, and in particular in testing for any type of pollutant that may be carried by an artesian sand, it is desirable that individual sands be isolated. Thus, a well which passes through several water producing formations is preferably isolated at each formation. This isolation enables fluid production to be obtained for instance if there were four formations of interest which required perforation, each of the four could be produced for one day and shut in for the next three days while the others are then produced. Alternately, it may be desirable to produce for just a short interval from each of the formations to obtain a test sample. In that instance, the test sample need only be a small sample or lot, perhaps a fraction of a liter. In a variety of circumstances, one can imagine why it is necessary to produce from a single formation into a well borehole, isolate that production and deliver that production fluid for testing or assay purposes. In any case, a number of variations can be implemented through the use of the present equipment so that a small sample isolated from commingling with other fluids from other formations is delivered. In one instance, it may be production for a week from a single formation while in another instance, it can be production of only a fraction of a liter. Commingling is prevented during production and also at the start and finish of production. Moreover, this enables surface control of the particular formation fluid so that such isolation is subject to control at the well head.
The present apparatus cooperates with a cased well borehole in which the cased well is cemented in place in the ordinary fashion and perforations are formed into the producing formations of interest. Production fluid flow is delivered from a particular formation into a set of perforations which flow into a plugged casing for production into a packer defined zone connected to a production tubing. The tubing includes a special joint which is installed at that region. This particular tubing joint has a outer cylinder which functions in the ordinary fashion to define the tubing string in the cased well borehole. On the interior, this particular tubing joint has, from the upper end, an anchor receiving receptacle. This profiled receptacle is an anchor for a tool that will be described to enable the tool to be anchored with certainty in the receptacle. The receptacle is cut with a set of encircling rings and shoulders which conform with and cooperate with mating keys which extend radially outwardly into the anchor receptacle. Below that, there is a polished cylindrical area. It cooperates with a seal that will be described. Below that, there is a movable sleeve which has a receptacle on the interior face of it. This receptacle is unique in its ability to accept only one type of key mechanism which inserts into it. The sleeve is in the up position initially to receive the unique, matching, profiled keys on the sonde. This enables latching to the sleeve. The sleeve has slots in it to permit production fluid to flow into an isolated zone in the well; the sleeve is immediately adjacent to upper and lower sleeve seal rings which define an area or region which is isolated. When the sleeve moves downwardly, the slots are positioned between the upper and lower seals so that the movable sleeve then opens the fluid flow pathway. So to speak, this sleeve functions as a control valve mechanism. It is a sliding sleeve functioning as a valve permitting formation fluid flow from the formation and through perforations in the casing member which is cemented in place at the formation of interest. The fluid flow is valved to enable flow into the production tubing. As noted, there are upper and lower seals which are adjacent to the moveable sleeve. The moveable sleeve is able to slide downwardly so that it can be moved from the initial closed condition into the open condition or position. There is another polished cylindrical area to receive a second seal for purposes to be described.
This moveable sleeve equipment is installed at each of the formations of interest in a production tubing for the formation. This type of equipment is installed so that the production control is initiated by the present apparatus which further includes a sonde which is lowered in a well borehole on an electric line. The line provides sufficient conductors to provide electrical power for operation and also has conductors for providing signals to operate specific valves in the apparatus. Moreover, it incorporates an electrical conductor pathway through the sonde which enables the conductors to connect with pressure isolation so that the electrical conductor pathway is protected from the intrusion of fluid. In addition to that, there is an externally located sleeve on the sonde which supports at its lower extremity a set of latch keys which extend into the anchor receptacle previously described that is located in the tubing joint. These keys are supported in a surrounding cage, and are able to extend radially outwardly through the window so that locking is accomplished, that is, where the keys fit into and match up with the profile in the anchor receptacle. This sleeve is telescoped in downward movement, the movement being sufficient to achieve radial extension outwardly of the keys in the anchor position. On the sonde interior, there is an electric motor controllably operated from the surface which connects with a lead screw on the interior. That screw supports a traveling nut, which, on screw rotation, is driven downwardly. The traveling nut has a stroke length which is sufficient to set into motion several sequential steps or movements involved in opening the moveable sleeve that is between the sonde and the production in the well borehole.
The moveable sleeve serves as a control valve as mentioned. The traveling nut which is advanced by the motor engages the top end of the sleeve by forcing it to move downwardly. Before that however is accomplished, there is the necessity of assuring connection with the sleeve by means of a coacting receptacle on this moveable sleeve in conjunction with latch keys forced radially outwardly into the receptacle. This receptacle on the moveable sleeve along with the receptacle thereabove assures that connection is made by the sonde at two locations, one to the moveable sleeve and the other to the tubing joint. The latch keys are extended radially outwardly into the receptacle on the moveable sleeve to make sure the connection. This is accomplished on the downward travel of the traveling nut and sleeve which repositions the slots in this moveable sleeve adjacent to the perforations into the formation so that formation fluid flow is received. Downward travel of this sleeve is extended until the sleeve locks at a desired location after travel.
The exterior of the sonde supports upper and lower seals which line up with particular polished cylindrical areas of the tubing joint to define an isolation zone. From the interior of the sonde, there are ports cooperative with passages extending along the length of the sonde. The passage conveniently extends towards the end of the sonde for communication with an electrically operated control valves. In one embodiment, control valves permit downward flow of fluid in the isolation zone into a first container, and there is a second container which is also filled through the same pathway. Briefly, one container in a preferred embodiment can be used to hold and store waste sample. This is the sample that is in the isolation zone defined between the sonde and the moveable sleeve prior to opening of the sleeve, and as desired, sample which is accumulated there after closing of the sleeve. There is a second container which can be used to store the pure sample directly flowing from the formation into this chamber or container.